When experimental errors are ignored in an experiment, the subsequent
analysis of its results becomes questionable. We develop tests to detect
systematic errors in quantum experiments where only a finite amount of data is
recorded and apply these tests to tomographic data taken in an ion trap
experiment. We put particular emphasis on quantum state tomography and present
three detection methods: the first two employ linear inequalities while the
third is based on the generalized likelihood ratio.Comment: 4+ pages, 2 figures, 1 table, published versio